Lubricating and corrosion-preventing composition



Patented Nov. 13, 1945 LUBRICATING AND CORROSION-PREVENT- IN GCOMPOSITION James E. Shields, Niagara. Falls, N. Y., and Ulric B. Bray,Palos Verdes Estates, Calif., assignors to Alox Corporation, New York,N. Y., a corporation of New York No Drawing. Application April14, 1943,

Serial No. 483,056

2 Claims. (Cl. 25.2-40.7)

This invention relates to the provision of improved lubricating andcorrosion-preventing compositions. In particular, it relates tocompositions adapted to lubricate and prevent the corrosion of smallfirearms such as pistols, rifles, automatic or sub-automatic rifles andmachine guns, and especially adapted to provide operationally effectivelubrication, and corrosion-prevention, at very low temperatures of use,at 50 F. or -70 F. or lower.

For the protection of such firearms, parts thereof, and accessoriestherefor, during shipment and storage in boxes or containers, it hasbeen conventional either to smear a heavy, normally solid grease likesubstance in thick layers over the surfaces of the arms or parts, oractually to imbed the same in a medium of such grease-like substance.The so-treated arms cannot be put to use (that is, fired) without firstremoving the protective material, because the latter is difiicult todeform at relatively normal room temperatures, and very difiicult todeform at lower than normal temperatures. Moreover, the conventionalprotective material does not possess satisfactory lubricatingproperties. Consequently, before arms are made ready for action all thisgrease-like material must be removed in its entirety by dissembling andwashing various parts in solvent, then reassembling and oiling with aliquid lubricant, which operations necessarily are time-consuming. Thisgrease-like substance is found very difficult to remove after remainingin storage for longer than periods of 8 months, particularly in respectto removing the substance in its entirety from th surfaces by cleansingwith solvents such as petroleum solvents. The material now used is knownto change physically and chemically at the interface after throughout awide range of temperatures including temperatures as low as 70 F. andwhich simultaneously are effective corrosionpreventives fo such firearms(and mechanisms) during shipment and storage. Another inventive objectis the provision of liquid preservative lubricant compositions of lowviscosity over wide ranges of temperatures, which compositions shall beeffective as corrosion-preventives when spread in extremely thin, oilyfilms (by dipping, brushing or spraying) over the surfaces of thefirearm parts or of the assembled firearms, which protective films neednot be removed when the firearms are put in operation but ratherconstitute improved lubricating films eifective for lubricating thefirearms of all temperatures down to as low as 70% F. or lower.

The above, and other, inventive objects are realized by the use of thehereinafter described normally liquid lubricating andcorrosion-preventing compositions. They have been found to givesatisfactory .lubrication. and protection against corrosion duringshipment, storage and operation of all types of small arms, andespecially satisfactory lubrication during the operation of machine gunswhen fired at temperatures as low as --70 F. The compositions areliquids of low viscosities oved wide ranges of temperatures, and provideadequate protection against corrosion of firearms and replacement partsduring shipment and storage by spreading an extremely thin coatingthereof by dipping, spraying or brushing the parts or assembledfirearms. It is unnecessary to remove these new preservative lubricantcompositions when the arms are put in operation.

Preferred specific preservative lubricant compositions in accordancewith the present invention have properties and characteristics fallingaging for periods over 8 months. It has been within the followingranges:

Flash oint F'. minimum 275 (by open cup method) Pour p bint: "1 1,maximum 0 to (by ASTM method) Viscosity, kinematic Centistokes at 100 F12.0 to 20.0 Centistokes at 30 F 2000 to 6000 Corrosion on copper,brass, bronze, aluminum,

magnesium, steel, etc i1 Protection against corrosion ProtectHand-blasted steel (SAE 1020) against Immersion corrosion Protectsand-blasted steel (SAE 10 found that objectionable, difficultly-solublesubstances are formed which are extremely difiicult to remove byordinary means. This substance resembles a gum-like material and isfound to be slightly soluble in alcohols or acetone.

It is an object of the present invention to provide normally liquidpreservative lubricant compositions, by which expression are here meantnormally liquid compositions which are effective lubricants for firearms(and other mechanisms) corrosion for 200 to 300 hours when tested in ahumidity cabinet maintained at 100 F., and to relative humiditzy.

0) against corrosion when immersed in 355% NaCl solution for 20 hours atroom temperature.

In addition to having the above properties, they permit, when used aslubricants for a .50 caliber M-2 basic aircraft machine gun maintainedat from -50 F. to -70 F., the automatic firing of 25 line rounds withone round in the gun chamber without stoppage of the guns operation.These compositions remain brilliantly clear when gradually cooled fromroom temperature to their solidification points, which desirableproperty indicates that no objectionable crystalline bodies,

which might interfere with or retard the firing action of a gun, willform therein during severe reduction in temperature.

The liquid preservative lubricant compositions of the present inventionare, in general, solutions, in selected light oils (hereinafter morespecifically described) of small amounts of alkaline earth metal(preferably calcium) soaps oi Alox acids, of lower alkyl esters of Aloxacids, and of selected anti-oxidants.

By Alox acids" are here meant the relatively high molecular weight,generally saturated, carboxylic acids derived from petroleum or similarmineral hydrocarbon mixtures by the Burwell process of liquid-phase,controlled, partial oxidation thereof (see U. S. Patents Nos. 1,690,768and 1,690,769). These Alox acids which are here used for preparing thealkaline earth metal soaps and lower alkyl esters are derived from theoxidation of petroleum fractions of lubricating oil grade, preferablyderived from the oxidation of well refined lubricating oil stocks whichare substantially free from crystalline bodies, and, desirably, alsosubstantially free from asphalts and unsaturated hydrocarbons. Highlyrefined, propane-extracted parafllne-base oils have. been found to beespecially suitable. Operable starting materials may range in specificgravity from 29 to 34, in viscosity (at 210 F.) from 40 to 60, and inviscosity index from 80 to 120. Typical is a lubricating oil having aspecific gravity of 32.0, a viscosity of 49.6, a viscosity index of 104,and 440 F. flash point.

Addition of such calcium soaps of Alox acids" to lubricating oilsdefinitely depresses the pour point of the oils. For example, when from3.5 to 4.5% of the calcium soaps is added to an oil or mixture of oilsof different viscosities showing the following pours, the pour point isfurther depressed, as shown:

Oil A, pour point 4'0 F Depressed to 60 F.

The preservative action toward steel of an oil solution of the aforesaidcalcium soaps is considerably weaker in the immersion test than in themoist air test. Thus, in the case of composition #5 of the above table,the coated steel panel showed corrosion after being immersed in tapwater for 48 hours, and corroded in a shorter time of immersion in a3.5% solution of NaCl in water. However, it has been found that theaddition of from 0.5% to 1.0% (by weight) of methyl esters of Aloxacids" to composition #5 gives a moist air test of 150-200 hours, a tapwater test of longer than 100 hours, and a 3.5% of NaCl solution test offrom 75 to 100 hours. Similar improvement as to immersion test resultsfollows generally from addition of these (or similar low molecularweight) alkyl esters of Alox acids to lubricating oil solutions ofcalcium soaps of Alox acid. Instead of the methyl esters there may beused the corresponding ethyl, propyl or butyl esters of the Alox acids.The Alox acids employed in forming the alkyl esters may be those derivedfrom partially oxidized mineral lubricating oils of the typeshereinbefore described.

The anti-oxidants which are used in preparing the compositions of thepresent invention are thio-ethers and include: thio-ethers of higheralkyl phenols such as amyl phenol and octyl phenol, and thio-ethers ofmon-atomic aliphatic alcohols having six or more atoms in the chain(straight, or branched). Preferably, the thioether of tertiary amylphenol is employed, in an amount of the order of 05-10% by weight. Thesethio-ethers are efiective in the composition to prevent excessiveoxidation of the latter when the same is subjected to relatively hightemperature, particularly, in rapid-firing guns such as Oil B, pourpoint F Depressed to 65 F.

Oil C, pour point 55 F Depressed to 70" F.

Oil D, pour point 65 F Depressed to 80 F.,

and lower.

Also, the calcium soaps of Alox acids exert a definite-anddesirable-corrosion-preventing action in the composition.

The degree of protection which the new preservative lubricantcomposition provides steel surfaces under'atmospheric exposure (moistair) is related to the amount of calcium (or other alkaline earth metal)soaps of Alox acids" present in said composition. Preferably, thecalcium soap is present in the composition in an amount from 1% to 4.5%,preferably from 3.0% to 4.5%, by weight. Illustrative of the variationare the following corrosion data: Panels of SAE .1020 ("low carbon)steel were coated with the coating compounds recited .in the tablebelow, and were exposed in a cabinet in which the atmosphere, keptmoving, was maintained at 95-10 relative humidity and at a temperatureof 100 F., corroded at the rates shown:

No. of hours before corro- Coating compound Sion appeared Lighttransformer oil of low pour point viscosity 9.5 centistokes at 100 rBetween 1 and 2hours.

2 Same oi l+l.0% Ca soaps" Between 5 and 7 hours.

3 Same o l+2.0% Ca soaps. Between 24 and 36 hours. 4 Same oyl+3.0% Casoaps. Between 150 and 200 hours. 5 Same o l+3.5 a Ca soaps Between 200and 300 hours. 6 Same oil-45 a Ca soaps Between 450 and 600 hours.

machine guns and sub-automatic machine guns: also, they are beneficialin holding in solution slight amounts of hydroxy hydrocarbon soaps whichmay appear in .the alkaline earth metal soaps of the "Alox acids.

The light oil which is used as the diluent or solvent component of thepresent compositions is a highly refined petroleum lubricating oil oflow pour test, e. g., a highly refined transformer oil. Preferably,there is used an oil which has the following properties andcharacteristics:

Flash point, minimum 300 F. Pour point 50 to 65 F. Viscosity at Fcentistokes 9.5-10.0 Viscosity at 30 F do 1500-2000 Engler distillationrange:

Initial boiling point 250-280 cent. 10% 308-310 cent. 50% 330-350 cent.Oxidation by Norma Hoffman bomb method 400 hours, not to exceed 25% drop01' initial pressure Gum. deposition Nil Color after 400 hours exposure-Not lower than #6 N. P. A. Water content N11 In this connection it isnoted that oils-of the same viscosity and distillation range-fromdifferent sources show a wide variation as to rate of evaporation frommetal surfaces. Thus, an oil from California crude evaporates from ametal surface much faster than does an oil (of the same viscosity anddistillation range) from Pennsylvania crude, and an oil from Venezuelancrude evaporates somewhat more slowly than assacoo 3 does the oil fromPennsylvania crude. Because of these facts, it is preferred to employ,as the diluent or "solvent component of the present compositions, oilsrefined from Venezuelan or Pennsylvania crudes.

For preparing the calcium soaps component of the compositions of thepresent invention the procedure may be as follows: The starting material(that is, the oil) is oxidized, by the Burwell process, for a period offrom 4 to 6 hours or until the reaction mass has acquired an acid numberof from 12 to 1'7. The partially oxidized mass is washed with water toremove any water-soluble components. The washed mass is then treatedwith aqueous caustic alkali to saponify the saponifiable componentsthereof, and the resulting mixture is thereafter maintained for sometime in a quiescent state in order to permit substantially completeseparation between the resulting soaps and the unsaponifiable componentsof the mass. After such separation, the soaps-containing layer isremoved from the settling chamber and the alkali metal (e. g., sodium)soaps are recovered and converted to calcium soaps by reaction withcalcium chloride. The calcium soaps are washed free from chlorides, andare blended with oil for further treatmentand filtration. The oilselected for the blending step preferably is the same. as thatsubsequently to be used in extending the eventual concentrate to thefinal preservative lubricant composition.

Complete conversion of the alkali metal soaps of the Alox acids tocalcium soaps is not effected by the double decomposition method. withcalcium chloride, and hence it is necessary or at least advisable tocomplet the conversion to calcium soaps by liming the product; This stepis effected by treating the material; at relatively high temperature (1.e., at above 100 C.) with an excess of calcium hydroxide. Water isdriven off by heating the limed material to a top .temperature of say160 C. The liming treatment not only converts residual sodium soaps tocalcium soaps but also neutralizes any acids which may have beenoccluded in the soap mixture. The liming treatment may be practicedimmediately after the double decomposition with calcium chloride, butpreferably is practiced after the product of the double decompositionstep has been blended with sufficient oil to make the "concentrate"hereinafter described.

After the liming, the limed material is maintained in quiescent statefor several hours to permit the settling out of excess lime, and is thenfiltered.

The filtered limed blend of calcium soaps in oil is then combined withthe lower alkyl esters component and with the thio-ether component,whereby to complete the preparation of a concentrate which may besuitably extended with a further portion of the aforesaid diluent oil.or with a mixture of diluent oils, to provide the final preservativelubricant composition. The conpreferably 50 F., or lower 10-15Thio-ether of tertiary amyl phenol (or equivalent oxidation-depressingthioether compound) 0.5-1.0 The aforesaid methyl (or other lower alkyl)esters of Alox acids 0.5-1.0

To convert this concentrate to the final preservative lubricantcomposition the same is extended with sufllcient "diluent oil to makethe total 100 parts by weight. The diluent oil may consist of a highlyrefined oil having the properties hereinbefore set out, e. g., atransformer oil of low pour point; preferably 50 F. or lower, or (aswhere a less extremely low temperature product i indicated) it mayconsist of a major amount of the latter with a minor amount (say, 10 to15 parts by weight) of another oil such, for instance, as aMid-Continent oil having a pour point between 0 and l0 F. and aviscosity of 180-250 S. U. V. at 100 F.

We claim:

1. A preservative lubricant composition substantially consisting of ahighly refined hydrocarbon oil derived from Venezuelan or Pennsylvaniancrude oil and having a pour point at least as low as -@40 F. containingdissolved therein from about 3.0% to about 4.5% by weight of calciumsoaps of acids derived from the oxidation of a petroleum lubricating oilsubstantially free from crystalline bodies, asphalts and unsaturatedhydrocarbons, and from about 0.5% to about 1.0% by weight of lower alkylesters of said acids, the resulting solution also containing a smallamount of an oxidation-depressing thio-ether of an alcohol, saidpreservative lubricant composition having a pour point at least 20 F.below that of the hydrocarbon oil component of the composition.

2. A preservative lubricant composition substantially consisting of ahighly refined hydrocarbon oil having 8. Pour point not higher thanabout 40 F. containing dissolved therein calcium soaps and methyl estersof acids derived from the oxidation of petroleum lubricating oilssubstantially free from crystalline bodies, asphalts and unsaturatedhydrocarbons, the calcium soaps of said acids being present in an .1amount of from about 3.5% to about 4.5% by weight and the methyl estersof said acids being present in an amount of from about 0.5% to about1.0%, and a relatively very small amount of an oil-solubleoxidation-depressing thio-ether, said composition having a pour test atleast 20' F. below that of the hydrocarbon oil component 01' thecomposition.

JAMEB E. SHIELDS.

ULRIC B. BRAY.

